Modular air intake heater

ABSTRACT

A modular intake heater for an internal combustion engine. The heater includes a first holder, a second holder, a heating element positioned between the first and second holders, and a retainer mechanism coupling the first holder to the second holder to retain the heating element therebetween. In alternative embodiments of the invention the retainer mechanism includes a clip mechanism and a grommet lockingly engaging a bolt disposed within passages defined by the first and second holders.

This is a continuation-in-part of U.S. patent application Ser. No.09/060,808, filed Apr. 15, 1998.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention generally relates to an apparatus for heating theair/fuel mixture entering the cylinders of an internal combustionengine. More particularly, the invention relates to a modular electricheater adapted for mounting within an intake passage of the engine.

2. Discussion

The air/fuel mixture entering the cylinders of an internal combustionengine is commonly heated to increase fuel economy and responsiveness tostarting as well as to decrease pollutant discharge. One type of intakeheating device generally includes a pair of gaskets surrounding aheating coil or grid disposed between the carburetor and the air intakemanifold as shown in U.S. Pat. No. 4,020,812 to Hayward and U.S. Pat.No. 4,106,454 to Henlis. The gaskets in these devices prevent air leaksinto and out of the engine manifold and thermally and electricallyisolate the grid from the intake structure. However, as recognized andaddressed in U.S. Pat. No. 5,595,164 ("the '164 Patent"), entitled "LowProfile Intake Manifold Heater", issued Jan. 21, 1997, gasket wear oraging may eventually short the electric circuit through the heatingelement.

While the heater of the '164 Patent addresses the short circuitingconcerns, it uses a large mounting structure that supports the heatingelement within the manifold. This mounting structure is expensive toship to customers, cumbersome to work with, and requires externalgaskets to seal against the manifold. In addition to the manufacturingand shipping costs associated with the mounting structure, the requisitegaskets increase the overall joint thickness and the difficulty ofconstructing a joint that will both seal and provide structural supportto the intake system.

In view of the above concerns as well as manufacturers' ever presentdesire to reduce manufacturing costs and complexity, a need exists for amodular heater device that may be easily and inexpensively manufactured,shipped, and installed in a variety of applications.

SUMMARY OF THE INVENTION

The present invention addresses the above identified needs by providinga modular air intake heater that includes a first holder, a secondholder, a heating element coupled to the first holder and the secondholder, a biasing element, and a retainer mechanism coupling the firstand second holders against the urging of the biasing element. Themodular heater includes a mounting assembly that facilitates use of theheater in a variety of different housings, manifolds or ducts therebyreducing the need to inventory multiple heater configurations. Manymanufacturers place a high value on reducing the total number ofdifferent components they are required to maintain in inventory. Productinterchangeability decreases the physical amount of space required tostore components and lessens the documentation burden of trackingsimilar components throughout the engineering and assembly process. Themounting assembly of the modular heater reduces the overall size of theheater while the retainer mechanism maintains the heater components in astructurally secure configuration for transportation and installation.

In addition, the mounting assembly and overall heater configurationeliminates the need for additional sealing members such as gasketswithin the joint connecting the intake to the engine. By removing anygaskets or flange type housings for mounting the heater element, thejoint integrity and cost of the assembly is positively affected.

BRIEF DESCRIPTION OF THE DRAWINGS

The various advantages of the present invention will become apparent toone skilled in the art by reading the following specification andappended claims, and by referencing the following drawings in which:

FIG. 1 is a top view of the modular heater assembled and mounted to anintake manifold of an internal combustion engine;

FIG. 2 is a sectional view taken at location 2--2 shown in FIG. 1 andillustrating the attachment of the heater device to the intake manifold;

FIG. 3 is an exploded perspective view of a first embodiment of themodular air intake heater;

FIG. 4 is a perspective view of the modular heater device shown in FIG.3 assembled for shipment;

FIG. 5 is an exploded view of the first holder;

FIG. 6 is an exploded view of the second holder;

FIG. 7 is a sectional view similar to FIG. 2 illustrating a secondembodiment of a heater device according to the present invention whichis attached to an intake manifold;

FIG. 8 is an exploded perspective view of the heater device shown inFIG. 7;

FIG. 9 is a elevational view of the locking grommet; and

FIG. 10 is a sectional view of the locking grommet taken along the line10--10 shown in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a first embodiment of the modular airintake heater 10 of the present invention is connectable to an intake 12of an internal combustion engine in communication with a passage 13(FIG. 1) of intake 12. As will be described in greater detailhereinafter, a coupling assembly 15 (FIG. 2) couples the heater 10 tothe intake 12 at predetermined discrete points. The coupling assembly iselectrically and thermally isolated from the intake in a mannergenerally known in the art.

As best illustrated in FIGS. 2-4, heater 10 includes a first holder 14,a second holder 16, and a serpentine heater element 18. FIGS. 2-6 depicta first embodiment of a retainer mechanism 20 coupling first holder 14to second holder 16 against the biasing force of a biasing element suchas wave springs 34 and 134 shown in FIGS. 5 and 6, respectively.Retainer mechanism 20 (FIG. 4) couples first and second holders 14 and16 to each other against the biasing force of a biasing element such aswave springs 34 and 134 shown in FIGS. 5 and 6, respectively, anddescribed in detail hereinafter.

With reference to FIGS. 3 and 4, retainer mechanism 20 includes a firstset of clip tabs 22 and a second clip tab 24. Second clip tab 24 isconfigured to engage first set of clip tabs 22 (FIG. 5) in a snap-fitcoupling that is also described in detail below. The snap-fit couplingsecurely retains heater element 18 between first and second holders 14and 16 as shown in FIG. 4. The structural configuration of modularheater 10 provides numerous advantages over the prior art including easeof shipment as the heater is modular in the sense that it does notrequire a large or complex mounting frame to securely intercouple theheater elements for shipment nor to secure the modular heater to theengine for operation. Additionally, the retainer mechanism 20 of thepresent invention withstands the harsh temperature and vibrationalenvironment within an internal combustion engine.

Turning now to FIGS. 5 and 6, the structural configuration andengagement of first holder 14, second holder 16, and retainer mechanism20 will be described in detail. As shown in FIG. 5, first holder 14includes a housing 25 preferably stamped from a stainless steel sheet.Housing 25 defines a "C" shaped channel 32 bounded on three sides byopposed side walls 26 and 28 and end wall 30.

Wave springs 34, also preferably formed of stainless steel, aredisposable within channel 32 to engage end wall 30 at ends 36 and 38 aswell as a center recess 40. Thermal and electric insulators 42 are alsodisposable within channel 32 to engage and capture springs 34 betweenend wall 30 and insulators 42. Those skilled in the art will appreciatethat springs 34 urge insulators 42 away from end wall 30 and intoengagement with stops 44 which extend inwardly into channel 32 from sidewalls 26 and 28. Insulators 42 include cavities 48 to accommodate andposition heating element 18 therewithin. It is contemplated thatinsulators may be formed of a ceramic material known in the art toprovide the desired thermal and electrical insulating properties.

First clip tabs 22 are illustrated in FIG. 5 to include a body 50integral with one of side walls 26 and 28 and a catch 52 at the terminalend of body 50. Catches 52 extend inwardly toward channel 32 from body50 as shown in FIG. 5. As will be described in detail below, catches 52are configured and positioned for snap-fit engagement with outwardlyextending catches formed on second tab 24.

Heater 10 includes a mounting assembly 17 (FIG. 2) cooperative withcoupling assembly 15 for connecting the modular heater 10 to themanifold 12 of the internal combustion engine. More specifically, firstholder 14 includes side flanges 54 and 56 having apertures 58 and 60formed therein to accommodate bolt connections to manifold 12 ashereinafter described with reference to FIGS. 1 and 2. A similar flangeand aperture configuration is provided in second holder 16 and heatingelement 18 as is described below.

As shown in FIG. 6, second holder 16 is configured substantially thesame as first holder 14 with the exception of second tab 24.Accordingly, the components of second holder 16 are referred to hereinby numerals increased by one hundred relative to the numbers used todescribe first holder 14. For completeness, it is noted that springs 134of second holder 16 include a pair of recesses 140 and 141 that engageend wall 130 of housing 125. Other than the configuration of springs 134and the below described configuration of second tab 24, those skilled inthe art will appreciate that the configuration and interrelation of sidewalls 126 and 128, channel 132, wave springs 134, insulators 142, stops144, cavities 148, flanges 154 and 156, and apertures 158 and 160 aresubstantially the same as the corresponding components described abovewith reference to FIG. 5.

Second clip tab 24 is a stainless steel tab member shaped to generallyconform to the configuration of housing 125 and includes opposed legs150 and 151 extending upwardly from a bottom plate 155. The terminal endof each leg 150 and 151 includes an outwardly extending catch 152 and153, respectively. Those skilled in the art will appreciate that thesecond clip tab 24 may be formed or stamped integral with housing 125 orconnected thereto via a spot weld, rivet, bolt, or other connectionknown in the art such as at opening 162 in end wall 130.

To assemble modular heater 10, first holder 14 and second holder 16 areconfigured as shown in FIGS. 5 and 6, respectively, and heating element18 is properly positioned relative to first holder 14 by seating withininsulator cavities 48. A bolt 64, with appropriate insulators such as awasher 90 and sleeve 92, is disposed through apertures 80 and 66 andheating element 18 is seated in cavities 148 of second holder 16. Anexternal force is then supplied to displace first holder 14 towardsecond holder 16 i.e., along the axis defined by arrow 68 (FIG. 3),thereby compressing wave springs 34 and 134. Legs 150 and 151 of secondtab 24 are displaced toward one another to allow the catches 152 and 153thereof to pass catches 52 of first clip tab 22. Legs 150 and 151 arethen released and the forces of wave springs 34 and 134 are allowed tourge the respective catches into engagement.

Modular heater 10 may now be handled and/or shipped separately to an enduser without additional assembly steps required. The shape of thecatches 52, 152, and 153 allows movement of first holder 14 relative tosecond holder 16 in the direction of arrow 70 (FIG. 4) but restrictsmovement of the holders away from one another along the axis of arrow 68(FIG. 3). This float provides the assembler an extra degree of freedomfor alignment of apertures 58 and 60 with apertures 158 and 160 ofsecond holder 16 or other features such as the mounting holes formedwithin intake manifold 12. It is preferred that bolts 86, withappropriate insulating sleeves 92 and washers 90, are positioned asshown in FIGS. 3 and 4 and hereinafter described so as to furthersimplify the later connection of heater 10 to manifold 12.

Those skilled in the art will appreciate that while the retainermechanism 20 is illustrated and described herein as including first andsecond clip tabs 22 and 24, other coupling components generally known inthe art may be used with the present invention. More particularly, it iscontemplated that the retention function may be performed orsupplemented through the use of straps or binders disposed aboutselected portions of the heater 10.

For completeness and in reference to FIG. 3, it should be noted thatserpentine heater element 18 includes a center aperture 80 as well asend tabs 72 and 74 each with apertures 76 and 78, respectively. Thesetabs and apertures form part of the mounting structure of heater 10which, in the preferred embodiment illustrated and described herein,cooperates with the bolt connectors of coupling assembly 15 as is mostclearly illustrated in FIG. 2. Those skilled in the art will appreciatethat heating element 18 is formed of an electrically resistant materialthat generates heat when connected to a power source as hereinafterdescribed.

As best seen in FIGS. 1 and 2, modular heater 10 is connectable tointake manifold 12 through coupling assembly 15. Because the function ofmodular heater 10 is based on electrical resistance within heaterelement 18, coupling assembly 15 includes bolts 86, nuts 88 insulatingwashers 90 and sleeves 92 to avoid shorting the circuit. As shown inFIG. 2, each of bolts 86 is electrically connected to a power source 93for communicating current to heating element 18. The bolt 86, nut 88,and heating element 18 are electrically isolated from manifold 12 andfirst and second holders 14 and 16, respectively, by the selectiveplacement of insulating washers 90 and sleeve 92. Those skilled in theart will appreciate that a variety of insulators generally known in theart may be used in numerous configurations to properly isolate thecurrent from potential sources of short circuiting. Bolt 64 iselectrically connected to ground to complete the electric circuitsthrough heating element 18. Those skilled in the art will appreciatethat while a specific current configuration is illustrated in FIG. 2,the electrical connections between the heating element, power source,and ground may be modified without departing from the scope of theinvention as defined by the appended claims. Those skilled in the artshould also appreciate that a jumper bar 94 such as that illustrated inFIG. 1 may be used to simplify the ease of electrical connection of theheating element to the power source. Similarly, as shown in FIG. 7, thecoupling components of modular heater 210 are insulated from manifoldhousing 212 by selective placement of insulating washers 290 and lockinggrommets 410.

It should be appreciated from the above description that the modularheater of the present invention does not negatively impact the integrityof the mechanical joint between intake manifold 12 and the engine due toadditional gaskets, flanges, or heating elements that may shift,compress or wear over time. Secondly, an assembler installing modularheater 10 need not be concerned with handling or assembling multipleindividual heater components. Rather, heater 10 can be secured to intakemanifold 212 through the use of a threaded nut 88 with an appropriateinsulating washer 90.

FIG. 7 depicts a second embodiment of the modular heater device 210attached to intake manifold 12. The function and components of thisembodiment are generally the same as those previously described withreference to FIGS. 1-6. Accordingly, those skilled in the art willappreciate that modular heating device 210 provides the advantagesdiscussed herein. For clarity, similar components are labeled with likenumerals increased by 200.

As shown in FIG. 8, modular heater 210 includes a retainer mechanism 220having three locking grommets 410 constructed from a resilientinsulating material such as teflon. Locking grommets 410 are eachconfigured to engage bolts 264 and 286 in a snap-fit coupling thatretains heater element 218 between first and second holders 214 and 216.As shown in FIGS. 9 and 10, each locking grommet 410 includes acylindrical sleeve 412 formed about a grommet axis 413 (FIG. 10) to forma passage 415, a flange 414 extending radially outward from sleeve 412,and a barb 416 circumscribing passage 415. It will be appreciated thatpassage 415 is sized to accommodate one of bolts 286 and 264 while barb416 protrudes inwardly from an inner surface 418 of sleeve 412 proximateto a rear face 419 thereof to effectively reduce the size of passage 415to a dimension less than the outer diameter of bolts 264 and 286.

Modular heater 210 is illustrated in its assembled state in FIG. 7. Fromthis description and the appended drawings, it will be appreciated thatthe assembly of modular heater 210 is similar to that described abovewith reference to FIGS. 1-6. However, after positioning holders 214 and216 relative to heating element 218 and arranging the various washers,nuts, and bolts as described, locking grommets 410 are positioned overbolts 264 and 286 and axially displaced along the bolts toward heatingelement 218 until flange 414 contacts first holder 214. As lockinggrommets 410 are displaced, barb 416 is compressed and/or urged radiallyoutward allowing the barb to pass at least one thread of bolts 264 and286. Once assembled, the wave springs urge holders 214 and 216 away fromone another. This biasing force is resisted by the engagement of barb416 with the thread of bolts 264 and 286. It should be appreciated thatthe term thread as used herein encompasses standard pitched threads aswell as ribs or cylindrical grooves that may function to lockinglyengage barb 416.

A chamfer 420 is provided along the exterior surface of sleeve 412 tofacilitate positioning of locking grommet 410 within housing 212. Asshown in FIG. 7, sleeve 412 is sized such that it will engage housing212. Accordingly, upon connection of modular heater 210 to housing 212,the resiliency of locking grommet 410 allows the grommet to compressduring assembly to form a non-conductive seal area 421 between heater210 and housing 212.

The foregoing discussion discloses and describes two exemplaryembodiments of the present invention. One skilled in the art willreadily recognize from this discussion, and from the accompanyingdrawings and claims, that various changes, modifications and variationscan be made therein without departing from the spirit and scope of theinvention as defined in the following claims.

What is claimed is:
 1. A heating device for use in an internalcombustion engine comprising:a first holder having a first aperture; asecond holder having a second aperture; a heating element positionedbetween said first and second holders; biasing means for urging one ofsaid first holder and said second holder away from the other of saidfirst holder and said second holder; and a retainer mechanism couplingthe first holder to the second holder against the urging of said biasingmeans and to retain the heating element between said first and secondholders, said retainer mechanism including a fastener disposed withinsaid first and second apertures and a locking grommet engaging saidfastener in a snap-fit coupling.
 2. The heating device of claim 1wherein the retainer mechanism includes a first clip coupled to thefirst holder and a second clip coupled to the second holder, said firstclip engaging said second clip to couple the first holder to the secondholder against the urging of the biasing means.
 3. The heating device ofclaim 2 wherein the first clip includes a body and a catch projectinginwardly from the body, wherein the second clip includes a second bodyand a catch projecting outwardly from the second body, and wherein thecatch of the first holder engages the catch of the second holder tocouple the first holder to the second holder against the urging of thebiasing means.
 4. The heating device of claim 3 wherein said first clipis integral with said first holder.
 5. The heating device of claim 1wherein the first and second holders each contain an aperture forreceiving a coupling mechanism adapted to couple the heating device toan engine.
 6. The heating device of claim 1 wherein the biasing meanscreates a biasing force acting in a first direction and wherein theretainer mechanism allows movement of the first holder relative to thesecond holder in a second direction normal to the first direction. 7.The heating device of claim 1 wherein said first holder includes ahousing defining a channel and a stop, said heating device furtherincluding an insulator in said channel, said biasing means urging saidinsulator against said stop.
 8. The heating device of claim 1 whereinsaid fastener is a bolt.
 9. The heating device of claim 1 wherein thelocking grommet includes a sleeve having an inner surface defining apassage, said locking grommet having a barb projecting inwardly from theinner surface of the sleeve, and wherein the fastener includes a thread,said fastener disposed in said passage such that the barb of the lockinggrommet engages the thread of the fastener to couple the first holder tothe second holder.
 10. The heating device of claim 9 wherein the lockinggrommet is constructed from a resilient insulating material.
 11. Aninternal combustion engine for use in a vehicle comprising:an intakedefining a passageway; and a modular heating device coupled to theintake in heat transfer relationship with the passageway, said modularheating device includinga first holder having a first aperture, a secondholder having a second aperture, a heating element positioned betweenthe first and second holders, biasing means for urging one of said firstholder and said second holder away from the other of said first holderand said second holder, and a retainer mechanism coupling the firstholder to the second holder against the urging of the biasing means andto retain the heating element therebetween, said retainer mechanismincluding a fastener disposed within said first and second apertures anda locking grommet sealingly engaging said fastener and said intake. 12.The engine of claim 11 further including a connecting mechanism forremovably coupling the heating device to the intake.
 13. The engine ofclaim 11 wherein said retainer mechanism includes a first clip coupledto said first holder and a second clip coupled to the second holder,said first clip engaging said second clip to couple the first holder tothe second holder against the urging of the biasing means.
 14. Theengine of claim 12 wherein the locking grommet includes a sleeve havingan inner surface defining a passage, said locking grommet having a barbprojecting inwardly from the inner surface of the sleeve, wherein thefastener includes a thread, said fastener disposed in said passage suchthat the barb of the locking grommet engages the thread of the fastenerto couple the first holder to the second holder.
 15. The engine of claim14 wherein said locking grommet engages said intake to form aninsulating seal therebetween.
 16. A method for constructing a modularair intake heater comprising the steps of:obtaining a first holderhaving a first aperture, a second holder having a second aperture, aspring, a locking grommet having a sleeve and a heating element;positioning said heating element and said spring between said first andsecond holders; displacing one of said first holder and said secondholder toward the other of said first holder and second holder againstthe urging of said spring; and axially disposing a fastener within saidfirst aperture, said second aperture and said sleeve to interconnectsaid first holder and said second holder, said fastener adapted to besecured without necessity of rotation.
 17. The method of claim 16further including a clip mechanism having a first tab coupled to saidfirst holder and a second tab coupled to said second holder and whereinthe step of coupling said first holder to said second holder includesplacing said first tab in engagement with said second tab.
 18. Themethod of claim 16 wherein said first holder and said second holder eachinclude an aperture, wherein said fastener includes a threaded bolt andsaid locking grommet defines a passage having a barb projecting inwardlyinto said passage, and wherein the step of axially disposing saidfastener within said sleeve includes displacing said bolt within thegrommet passage such that said barb engages said bolt.
 19. A heatingdevice for use in an internal combustion engine comprising:a firstholder having a passage; a second holder having a passage; a heatingelement positioned between said first and second holders; and a retainermechanism coupling said first holder and said second holder andretaining said heating element therebetween, said retainer mechanismincluding a bolt disposed in said passages of said first and secondholders and a locking grommet engaging said bolt in a snap-fit coupling.20. The heating device of claim 19 further including biasing means forurging one of said first holder and said second holder away from theother of said first holder and said second holder.
 21. The heatingdevice of claim 19 wherein said retainer mechanism is adapted toremovably couple the heating device to an engine.
 22. The heating deviceof claim 19 wherein said first holder includes a housing defining achannel and a stop, said heating device further including an insulatorin said channel, said biasing means urging said insulator against saidstop.
 23. The heating device of claim 19 wherein the locking grommetincludes a sleeve having an inner surface defining a sleeve passage,said locking grommet having a barb projecting inwardly from the innersurface of the sleeve, and wherein the bolt includes a thread, said boltdisposed in said passage such that the barb of the locking grommetengages the thread of the bolt to couple the first holder to the secondholder.